The present invention relates to arrangements used in telephone networks for recording messages used to bill charges for interexchange calls.
Such arrangements operate by recording the relevant billing data for each toll call, or connection, in a so-called automatic message account, or AMA, message record. Typical message record fields are the originating and terminating telephone numbers and elapsed time of call. In a typical system, the message records, which are created for each call at a time substantially contemporaneous with the termination of the call, are transmitted from an originating switch to a message accumulation system. The latter distributes the accumulated messages to appropriate further processing systems which translate the AMA message records into the industry-standard "exchange message interface," or EMI, message record format. The EMI records are thereupon forwarded to a rating system which, inter alia, computes the toll charges applicable to the calls and adds an indication of those charges to the EMI record. The records thus formed are forwarded to a billing system in which they reside until processed to generate, typically, "hard copy" bills which are mailed to subscribers.
The invention more particularly relates to the generation of message records for long-distance--or so-called interexchange--calls, which involve the use of the facilities of a long-distance, or interexchange, carrier, also referred to as an IXC. In the United States, for example, AT&T, MCI and Sprint are three such IXCs. Each subscriber to local telephone service from a local exchange carrier, or LEC, such as New Jersey Bell, has an associated "primary interexchange carrier," or PIC, that was selected by or for the local subscriber. The local subscriber is said to be "PIC'd" to the associated IXC. When a long-distance call is initiated by the subscriber, the call is routed through the network of the originating subscriber's LEC, over the network of the PIC and, ultimately, through the network of the LEC which has as one of its subscribers the called party. At the termination of the call, a switch which carried the call--illustratively, a switch in the interexchange carrier's network--generates the AMA record as described above.